The development of communication infrastructure in recent years has made various supplementary services widespread in the field of communication. For example, in the case of telephone apparatuses, those which are capable of being connected not only to general telephone lines but also to wide area communication networks such as an IP telephone network and the Internet to receive various services such as a data communication service are widely used.
One of the functions of such a communication apparatus is a function of receiving an earthquake early warning which is distributed by a meteorological agency when an earthquake has occurred. An information delivery service called “the Earthquake Early Warning service” was launched in Japan on Oct. 1, 2007. This service is available to any user of a communication apparatus capable of receiving earthquake early warnings who has bought the communication apparatus and signed up with an Earthquake Early Warning delivery service provider.
On receiving an earthquake early warning at an occurrence of an earthquake, the communication apparatus uses regional information which is stored therein in advance such as the latitude/longitude information of the location where it is placed, to thereby calculate, for example, estimated earthquake intensity and an estimated arrival time of the principal shock (=part of the earthquake motion that is felt by the human body as the strongest shock, normally the S-wave).
The result of such calculation is notified to the user through, for example, an image displayed on a liquid crystal panel or sound output from a speaker. This allows the user to take actions to secure safety by, for example, hiding himself/herself under a table or turning off heat sources before the principal shock reaches his/her place from the hypocenter.
As an example of such an apparatus that is capable of receiving earthquake early warnings described above, Patent Literature 1 discloses an image processing apparatus capable of reducing the possibility of a secondary disaster following an earthquake, such as a fire, than before. This image processing apparatus is provided with communication control means which communicates with an external apparatus and power supply control means which changes the energization state of the apparatus.
When the communication control means receives an earthquake early warning from the external apparatus, the power supply control means is controlled to change the energization state. By controlling the power supply based on external information in this way, it is possible to prevent erroneous detection of an earthquake due to a shake other than an earthquake shake coming from a nearby construction work or caused by an accidental collision of something with the apparatus, to thereby secure safety without sacrificing convenience.
As another example such an apparatus that is capable of receiving earthquake early warnings described above, Patent Literature 2 discloses a portable earthquake early warning apparatus which is capable of collecting early information of an earthquake, based on which the apparatus judges whether or not it is necessary to give a warning before the arrival of the principal shock of the earthquake. This portable early earthquake warning apparatus is provided with: position information receiving means; earthquake early warning receiving means; and warning necessity judging means which judges the necessity of giving a warning before the arrival of the principal shock of an earthquake based on the position information and an earthquake early warning received by the respective receiving means.
With this apparatus, it is possible to give a warning, in railcars and automobiles, before the arrival of the principal shock of an earthquake, and this makes it possible to prevent serious damage by quickly stopping railcars or automobiles.